Commitments and Contigencies (Details Textual)	6 Months Ended
	Jun. 30, 2019 USD ($) t milestone	Dec. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Oct. 02, 2014 USD ($)
Business Acquisition [Line Items]
Palmarejo Gold Stream Agreement, Deferred Revenue Unamortized Balance	$ 12,200,000
Silvertip acquisition contingent consideration	$ 49,635,000	$ 25,000,000
Palmarejo gold production royalty
Business Acquisition [Line Items]
Production to be sold, percent				50.00%
Price per ounce under agreement				$ 800
Aggregate deposit to be received				$ 22,000,000.0
JDS Silver Holdings Ltd.
Business Acquisition [Line Items]
Silvertip acquisition contingent consideration			$ 50,000,000.0
Long-term Purchase Commitment, Milestones | milestone	2
JDS Silver Holdings Ltd. | First Milestone
Business Acquisition [Line Items]
Silvertip acquisition contingent consideration			25,000,000.0
Sustained minim and milling per day (in tones) | t	1,000
JDS Silver Holdings Ltd. | Second Milestone
Business Acquisition [Line Items]
Silvertip acquisition contingent consideration			25,000,000.0
Maximum payment			$ 25,000,000.0
Tonnes of Resource Added | t	3,700,000
Amount of resource required (in tonnes) | t	300,000
Commitment amount per resource amount reached	$ 5,000,000.0
Minimum Resource Tonnes Milestone | t	2,500,000